KR101346873B1 - Structured films having acoustical absorbance properties - Google Patents

Abstract

Structured films with sound absorption properties are disclosed. Also disclosed are methods of making and using the structured film.

Sound Absorption, Structured, Film, Tubular

Description

STRUCTURED FILMS HAVING ACOUSTICAL ABSORBANCE PROPERTIES}

The present invention relates to structured films having acoustic absorbance properties and to methods of making and using such structured films.

There is a continuing need in the art for articles that provide acoustic properties, including sound absorption properties.

Summary of the Invention

The present invention relates to a structured film capable of providing a predetermined area of acoustic properties including sound absorption properties. According to one exemplary embodiment of the present invention, a structured film includes a substantially flat film portion having a first major surface, a second major surface, and an average film portion thickness; And a plurality of tubular protrusions extending from the substantially flat film portion, wherein the one or more tubular protrusions are (i) holes extending into or through the substantially flat film portion from the first protrusion end on the first major surface, ( ii) a projection sidewall surrounding at least a portion of the aperture, the projection sidewall having an internal projection sidewall surface and an projection projection sidewall thickness, and (iii) a projection length extending a predetermined distance from the first projection end to the first major surface. And the ratio of the projection length to the average film portion thickness is at least about 3.5. In some embodiments, the ratio of protrusion length to average film portion thickness is at least about 4.0, and as high as about 10.0 or more.

In another exemplary embodiment of the invention, the structured film comprises a substantially flat film portion comprising a thermoformable material having a first major surface, a second major surface and an average film portion thickness; And a plurality of tubular protrusions extending from the substantially flat film portion, wherein the one or more tubular protrusions extend into or through the substantially flat film portion from the first protrusion end on the first major surface, (ii ) A projection sidewall surrounding at least a portion of the aperture and comprising the thermoformable material and having an outer projection sidewall surface, an inner projection sidewall surface and a projection sidewall thickness, and (iii) the second major surface from the first projection end. An end-to-end protrusion length extending to a predetermined length to a second end portion below.

In another exemplary embodiment of the present invention, the structured film comprises a substantially flat film portion comprising a thermoformable material having a first major surface, a second major surface and an average film portion thickness; And a plurality of tubular protrusions extending from the substantially flat film portion, wherein at least some of the tubular protrusions are (i) passing through the substantially flat film portion from a first protrusion end on the first major surface. A hole extending to a second projection end below the substantially flat film portion to provide an opening through the structured film, (ii) surrounding at least a portion of the hole, including the thermoformable material, and an outer protrusion sidewall surface A projection sidewall having an internal projection sidewall surface and a projection sidewall thickness, and (iii) an end-to-end projection length extending a predetermined length from the first projection end to the second projection end.

The present invention also relates to methods of making structured films as well as methods of using structured films in various applications. In one exemplary embodiment of the present invention, a method of using a structured film includes a sound absorption method in a predetermined area, the method comprising enclosing at least a portion of the area with the structured film.

These and other features and advantages of the present invention will become apparent after a review of the following detailed description of the disclosed embodiments and the appended claims.

The invention is further described with reference to the accompanying drawings.

1 illustrates an exemplary structured film of the present invention.

2A-2F illustrate possible cross-sectional shapes of exemplary tubular protrusions on the substantially flat film portion of the example structured film of FIG. 1 along line A-A.

3 is a side view of an exemplary structured film of the present invention attached to an additional layer.

4 is a side view of another exemplary structured film of the present invention attached to an additional layer.

5 is a schematic representation of an exemplary apparatus suitable for forming the structured film of the present invention.

6 is a graph of sound absorption coefficient versus frequency for an exemplary structured film of the present invention.

7 is a graph of impedance tube test data for an exemplary structured film of the present invention.

The present invention provides structured films that can provide acoustic properties including, but not limited to, energy dissipation, reflective / directing, or energy conversion (eg, the conversion of moving particles into thermal energy of dynamic particles due to friction). It is about. As used herein, the term “structured” refers to the topographical feature of the film, ie, the tubular protrusion along at least one major outer surface of the substantially flat film portion of the film. Say existence. The term “structured” is not used to describe the orientation of the tubular protrusion and the material (s) used to form the substantially flat film portion of the film.

The structured film has (1) excellent sound absorption properties; (2) have structural features that enable use in a variety of applications; (3) It can be manufactured in a cost effective manner. The invention also relates to methods of making structured films as well as methods of using structured films in a variety of applications, including sound absorption applications.

An exemplary structured film of the present invention is shown in FIG. 1. The exemplary structured film 10 of FIG. 1 has a substantially flat film portion 11 and a plurality of tubular protrusions 12 that extend over a first major surface 13 of the substantially flat film portion 11. ). As described in more detail below, the tubular protrusion 12 extends into or through the substantially flat film portion 11 from the first protrusion end 16 on the first major surface 13. A projection side wall 18 surrounding at least a portion of the hole 15, and a projection length L extending a predetermined distance from the first projection end 16 to the first major surface 13. In addition, exemplary structured film 10 may be attached to additional layers and / or components, as described below.

I. 3D Structured Film

As shown by the exemplary structured film 10 of FIG. 1, the three-dimensional structured film of the present invention includes a number of components that allow the structured film to be used in a variety of applications. For example, in some embodiments, the structured film of the present invention can provide excellent acoustic properties for a given substrate and / or area. A description of the possible components of the structured film of the present invention as well as the properties of the resulting structured film is provided below.

A. Structured Film Components

The structured film of the present invention may comprise one or more of the following components.

1. Substantially flat film part

The structured film of the present invention comprises a substantially flat film portion, such as the substantially flat film portion 11 of the exemplary structured film 10 shown in FIG. 1. The substantially flat film portion has a first major surface, a second major surface opposite the first major surface, and an average film portion thickness t extending from the first major surface to the second major surface. As used herein, the term “substantially flat film portion” is used to refer to the portion of the structured film of the present invention that surrounds and separates a plurality of tubular protrusions from each other. As shown in FIGS. 1-4, the substantially flat film portion has a flat film portion having an average film portion thickness t that is substantially less than the overall width w or length l of the structured film.

In the present invention, the " average film portion thickness " It is determined by measuring and calculating the average film portion thickness of the x film portion thicknesses. Typically, x is greater than about 3, preferably in the range of about 3 to about 10. Preferably, each measurement is taken at approximately an intermediate position between adjacent tubular protrusions to minimize any effect of the tubular protrusion on the measurement.

The substantially flat film portion of the structured film has an average film portion thickness that varies with the particular end use of the structured film. Typically, the substantially flat film portion has an average film portion thickness of less than about 508 micrometers (μm) (20 mils). In some embodiments, the substantially flat film portion has an average film portion thickness of about 50.8 μm (2.0 mils) to about 508 μm (20 mils). In another embodiment, the substantially flat film portion has an average film portion thickness of about 101.6 μm (4.0 mil) to about 254 μm (10 mil). In yet another embodiment, the substantially flat film portion has an average film portion thickness of about 101.6 μm (4.0 mil) to about 152.4 μm (6.0 mil).

The substantially flat film portion of the structured film may comprise one or more polymeric materials. Suitable polymeric materials include polyolefins such as polypropylene and polyethylene; Olefin copolymers (eg, copolymers with vinyl acetate); Polyesters such as polyethylene terephthalate and polybutylene terephthalate; Polyamides (nylon-6 and nylon-6,6); Polyurethane; Polybutene; Polylactic acid; Polyvinyl alcohol; Polyphenylene sulfide; Polysulfone; Polycarbonate; polystyrene; Liquid crystalline polymers; Polyethylene-co-vinylacetate; Polyacrylonitrile; Cyclic polyolefins; Or combinations thereof, but is not limited to such. In one exemplary embodiment, the substantially flat film portion comprises a polyolefin, such as polypropylene, polyethylene, or blends thereof.

The substantially flat film portion may further comprise one or more additives as described below. When present, the substantially flat film portion typically includes at least 75 weight percent of any one of the aforementioned polymeric materials and up to about 25 weight percent of one or more additives. Preferably, the substantially flat film portion comprises any one of the aforementioned polymeric materials as many as at least 80 weight percent, more preferably at least 85 weight percent, at least 90 weight percent, at least 95 weight percent, and 100 weight percent. Wherein all weights are based on the total weight of the substantially flat film portion.

Various additives may be added to the polymer melt formed from one or more of the aforementioned polymers and extruded to incorporate the additives into the substantially flat film portion. Typically, the amount of additive is less than about 25% by weight, preferably up to about 5.0% by weight, based on the total weight of the structured film. Suitable additives include fillers, stabilizers, plasticizers, tackifiers, flow control agents, cure rate retarders, adhesion promoters (eg silanes and titanates), adjuvants, impact modifiers. , Expandable microspheres, thermally conductive particles, electrically conductive particles, silica, glass, viscosity, talc, pigments, colorants, glass beads or bubbles, antioxidants, optical brighteners, antimicrobial agents, surfactants, fire retardants retardant), and fluoropolymers. One or more of the aforementioned additives reduce the weight and / or cost of the resulting substantially flat film portion, adjust the viscosity, change the thermal properties of the substantially flat film portion, or change the electrical, optical, density-related, liquid It can be used to impart a range of physical properties derived from the physical property activity of the additive, including barrier or adhesive adhesion related properties.

In one exemplary embodiment of the present invention, the substantially flat film portion comprises a single layer of thermoformable material, forming a first major surface and a second major surface and having the aforementioned average film portion thickness, wherein the thermoformable material Comprises one or more of the aforementioned polymers and optional additives. In a further exemplary embodiment of the present invention, the substantially flat film portion comprises a single layer of thermoformable material, forming a first major surface and a second major surface and having the aforementioned average film portion thickness, wherein the first layer The major surface and the second major surface are exposed (eg, not covered) so that they can be positioned and / or attached to the desired substrate.

2. Tubular protrusion

The structured film of the present invention further comprises a plurality of tubular protrusions extending over the first major surface of the substantially flat film portion, such as the tubular protrusion 12 of the exemplary structured film 10 shown in FIG. 1. . Preferably, the tubular protrusion is formed from the same thermoformable composition used to form the substantially flat film portion described above. In one preferred embodiment, the substantially flat film portion and the plurality of tubular protrusions comprise a continuous thermoformed structure formed of a single thermoformable composition comprising one or more of the aforementioned polymers and optional additives.

In another preferred embodiment, the substantially flat film portion and the plurality of tubular projections comprise (i) a continuous thermoformed structure formed from a single thermoformable composition, and (ii) a post film-post orientation after film formation. forming, projection-forming orientation). As used herein, the term “projection orientation after film formation” is used to describe the conventional process used to form protrusions and / or openings in a film. Such conventional processes are thermoforming, needle-punching, or other film punching steps used to form protrusions in pre-solidified film structures (eg, not molten film extrudate). Including but not limited to.

The plurality of tubular protrusions may be uniformly distributed over the first major surface of the substantially flat film portion or randomly distributed over the first major surface. In some embodiments, the plurality of tubular protrusions are uniformly distributed over the first major surface (and optionally the corresponding portion of the second major surface) of the substantially flat film portion.

In one exemplary embodiment, the structured film of the present invention comprises a plurality of tubular protrusions extending from a substantially flat film portion, wherein the one or more tubular protrusions are (i) from the first protrusion end above the first major surface. A hole extending into or through the substantially flat film portion, (ii) a protrusion sidewall surrounding at least a portion of the hole and having an outer protrusion sidewall surface, an inner protrusion sidewall surface, and a protrusion sidewall thickness, and (iii) a first protrusion end And a projection length L extending a predetermined distance from the first major surface, wherein the ratio of the projection length L to the average film portion thickness t is at least about 3.5. In another embodiment, the ratio of the projection length L to the average film portion thickness t is at least about 4.0. In yet another embodiment, the ratio of the projection length L to the average film portion thickness t is about 4.0 to about 10.0.

Tubular protrusions may have substantially similar protrusion lengths that vary from film to film depending on the ultimate end use of a given structured film. Typically, the tubular protrusions are from about 25.4 μm (1 mil) to about 1.27 cm (500 mil), more typically from about 50.8 μm (2 mil) to about 2.54 mm (100 mil), even more typically about 508 μm And a projection length L in the range of (20 mils) to about 1.02 mm (40 mils).

Tubular protrusions may be further described in terms of their protrusion hole length, protrusion hole diameter, and protrusion sidewall thickness, each of which may vary depending on the ultimate end use of a given structured film. Typically, the tubular protrusions are from about 25.4 μm (1 mil) to about 1.32 cm (520 mil), more typically from about 50.8 μm (2 mil) to about 2.79 mm (110 mil), even more typically about 508 μm Protrusion hole length ranging from (20 mils) to about 1.14 mm (45 mils); About 25.4 μm (1 mil) to about 6.35 mm (250 mil), more typically about 25.4 μm (1 mil) to about 2.54 mm (100 mil), even more typically about 25.4 μm (1 mil) to about Projection hole diameter in the range of 254 μm (10 mils); And from about 25.4 μm (1 mil) to about 508 μm (20 mil), more typically from about 25.4 μm (1 mil) to about 254 μm (10 mil), even more typically from about 25.4 μm (1 mil) to Protrusion sidewall thickness in the range of about 127 μm (5 mils).

The tubular projection can be further described in terms of the projection sidewall thickness with respect to the average film portion thickness t described above. In one exemplary embodiment, at least a portion of the tubular protrusion has a protrusion sidewall thickness that is equal to or greater than the average film portion thickness t of the substantially flat film portion.

As shown in FIGS. 2A-2F, the tubular protrusion may have various shapes and cross-sectional shapes. In some embodiments, the tubular protrusion has a second protrusion end located below the second major surface of the substantially flat film portion. In these embodiments, the structured film of the present invention comprises a plurality of tubular protrusions extending from the substantially flat film portion, wherein the one or more tubular protrusions are (i) substantially flat from the first protrusion end on the first major surface. A hole extending into or through the film portion, (ii) a projection sidewall surrounding at least a portion of the aperture and having an outer projection sidewall surface, an inner projection sidewall surface, and a projection sidewall thickness, and (iii) a second from the first projection end An end-to-end protrusion length extending a predetermined distance to the second protrusion end below the major surface. For example, as shown in FIGS. 2A and 2C-2F, the exemplary tubular protrusion 12 has a second end (located below the second major surface 14 of the substantially flat film portion 11). 17).

In some embodiments where the at least one tubular protrusion has a second end below the second major surface of the substantially flat film portion of the structured film, the at least one tubular protrusion is preferably a predetermined distance from the first protrusion end to the first major surface. Wherein the ratio of the upper protrusion length (eg, the protrusion length L) to the average film portion thickness t is at least about 3.5. More preferably, the ratio of the upper projection length (eg, projection length L) to the average film portion thickness t is about 4.0 to about 10.0.

The tubular projection may have a projection sidewall thickness that varies along the projection length (eg, projection length L or projection length between ends). As shown in FIGS. 2A-2F, the exemplary tubular protrusion 12 may have a protrusion sidewall thickness that remains substantially constant along the protrusion length (see, eg, FIG. 2B), or a protrusion sidewall that varies along the protrusion length. Thickness (see, eg, FIGS. 2A and 2C-2F). In one exemplary embodiment, the at least one tubular protrusion is a first wall thickness at the protrusion base, a second wall thickness at the first protrusion end, positioned between the first major surface, and between the protrusion base and the first protrusion end. Having a third wall thickness at the middle of the protrusion located at, where the first wall thickness and the second wall thickness are greater than the third wall thickness (see, eg, FIG. 2F). In another exemplary embodiment, the at least one tubular protrusion is a first wall thickness at the protrusion base, a second wall thickness at the first protrusion end, positioned between the first major surface, and between the protrusion base and the first protrusion end. Having a third wall thickness at the middle of the protrusion located at where the first wall thickness and the second wall thickness are less than the third wall thickness (see, eg, FIG. 2E).

In a further embodiment of the invention, the one or more tubular protrusions have a first cross-sectional area above the first major surface of the substantially flat film portion, a second cross-sectional area within the substantially flat film portion, and a second principal of the substantially flat film portion. Has a third cross-sectional area below the surface, where the first cross-sectional area is smaller than the second and third cross-sectional areas (see, eg, FIG. 2C). In some embodiments, the one or more tubular protrusions are in fluid communication with a hole (eg, hole 15) extending through the tubular protrusion (eg, the bubble portion shown in FIG. 2C (eg, FIG. 2C). 19)). In these embodiments, the bubble portion is present in (i) a substantially flat film portion, (ii) below the second major surface, or (iii) both (i) and (ii) (see, eg, FIG. 2C). Can be. In some further embodiments, the lower portion of the bubble portion can be removed to provide an opening that extends through the structured film from the first protrusion end to the second protrusion end. For example, a portion of the bubble 19 along the second end 17 of the tubular protrusion 12 shown in FIG. 2C can be removed by cutting the bubble 19 along the dashed line BB shown in FIG. 2C. Can be.

It should be appreciated that the tubular protrusion may have an external tubular protrusion cross-sectional shape that varies depending on the type of tool used to form the tubular protrusion and the desired cross-sectional shape. For example, the tubular protrusion may have an external tubular protrusion cross-sectional shape in the form of a circle, ellipse, polygon, square, triangle, hexagon, multi-lobed shape, or any combination thereof.

In another exemplary embodiment of the present invention, the one or more tubular protrusions (eg, holes that fully extend through the substantially flat film portion (with or without the need to remove some of the tubular protrusions as described above). (15)). As shown in FIGS. 2A-2B and 2D-2F, exemplary tubular protrusion 12 extends along a protrusion length from first protrusion end 16 to second protrusion end 17. ). As shown in FIGS. 2A-2B and 2D-2F, the cross-sectional area of the aperture 15 varies along the protrusion length from the first protrusion end 16 to the second protrusion end 17 (eg, 2A and 2D-2F) may be substantially constant (see, eg, FIG. 2B).

In one preferred embodiment, the structured film comprises a plurality of tubular protrusions extending from the substantially flat film portion, wherein at least a portion of the tubular protrusions is (i) substantially flat from the first protrusion end above the first major surface. A hole extending through the film portion to a second end below the substantially flat film portion to provide an opening through the structured film, (ii) surrounding at least a portion of the hole, the outer protruding sidewall surface, the inner protruding sidewall surface, and A projection sidewall having a protrusion sidewall thickness, and (iii) an end-to-end protrusion length extending a predetermined distance from the first protrusion end to the second protrusion end.

Typically, the tubular protrusion extends substantially perpendicular to the substantially flat film portion as shown in FIGS. 2A-2F, although other orientations of the tubular protrusion relative to the substantially flat film portion are within the scope of the present invention.

The tubular protrusion may be present along one or two major surfaces of the substantially flat film portion of the structured film with a desired tubular protrusion density and a tubular protrusion density that varies depending upon the end use of the structured film. In one exemplary embodiment, the tubular protrusion is along one or two major surfaces of the substantially flat film portion of the film structured to a tubular protrusion density that is up to about 1000 protrusions per cm 2 of the outer surface area of the substantially flat film portion. Typically, the tubular protrusion is present along one or two major surfaces of the substantially flat film portion of the film structured to a tubular protrusion density ranging from about 10 protrusions per square centimeter to about 300 protrusions per square centimeter of the outer surface area of the substantially flat film portion. do.

3. optional additional layer

The structured film of the present invention may include one or more optional layers in combination with the structured film components described above. The one or more additional layers are (i) on and / or in contact with the tubular protrusion end (eg, the first protrusion end 16) extending above the first major surface of the substantially flat film portion of the structured film, ( ii) on and / or in contact with a tubular protrusion end (e.g., second protrusion end 17) extending below a second major surface of the substantially flat film portion, and (iii) a second of the substantially flat film portion. On and / or in contact with the major surface (e.g., the second major surface 14), in (iv) both (i) and (ii), or (v) both (i) and (iii) May exist.

Suitable additional layers include fabric layers (eg, woven, nonwoven, and knitted fabrics); Paper layer; Color containing layers (eg, printing layers); Sub-micron fiber layers, such as those disclosed in US Patent Application No. 60 / 728,230, the disclosure of which is incorporated herein by reference in its entirety; Foam; Layer of particles; Foil layer; film; Decorative cloth layers; Membranes (ie films having controlled permeability, such as dialysis membranes, reverse osmosis membranes, etc.); Netting; Mesh; Tubes that carry various fluids or layers of wires that carry electricity, such as wiring and tubing networks (i.e., wiring networks for heating blankets and tubing networks for coolant flow through the cooling blankets) Group of pipes); Or combinations thereof, but is not limited to such.

 In one exemplary embodiment, the first additional layer is positioned over and attached to the first protrusion end of the tubular protrusion of the structured film of the present invention. Such a composite article is shown in FIG. 3. As shown in FIG. 3, the lower outer surface 21 of the first additional layer 20 is positioned over and in contact with the first protruding end 16 of the exemplary structured film 10. In this exemplary embodiment, the first additional layer 20 is for example a color containing layer, a nonwoven fabric, a woven fabric, a knitted fabric, a foam layer, a film, a paper layer, a layer of particles, a foil layer, a decorative cloth layer, Membrane, reticular, mesh, wiring or tubing networks; Or any combination thereof.

In further exemplary embodiments, the second additional layer may be located on and attached to the second major surface of the structured film of the present invention or the second protrusion end of the tubular protrusion. Such composite articles are shown in FIGS. 3-4. As shown in FIG. 3, the upper outer surface 31 of the second additional layer 30 is located on and in contact with the second protrusion end 17 of the exemplary structured film 10. In this exemplary embodiment, the second additional layer is, for example, a color containing layer, a nonwoven fabric, a woven fabric, a knitted fabric, a foam layer, a film, a paper layer, a layer of particles, a foil layer, a decorative cloth layer, a film, reticular Mesh, wiring or tubing networks; Or any combination thereof.

As shown in FIG. 4, the lower outer surface 21 of the first additional layer 20 is located on and in contact with the first protruding end 16 of the exemplary structured film 10, and the second additional surface 20. The upper outer surface 31 of the layer 30 is located on and in contact with the second major surface 14 of the exemplary structured film 10.

4. Attachment Attachment Device )

The structured film (or composite article comprising the structured film) of the present invention may further include one or more attachments that allow the structured film (or composite article) to be attached to the substrate. For example, adhesives can be used to attach a structured film (or composite article) to a given substrate. Suitable adhesives include, but are not limited to, pressure sensitive adhesives (PSA), heat activated adhesives or combinations thereof. In addition to the adhesive, other attachments may be used. Suitable attachments include, but are not limited to, any mechanical fasteners such as screws, nails, clips, staples, stitching, threads, hook and loop materials, and the like.

One or more attachments may be used to attach the structured film (or composite article) to various substrates. Exemplary substrates include vehicle components; Vehicle interior (ie, cabin, power room, trunk, etc.); Walls of the building (ie, interior or exterior walls); The ceiling of the building (ie, inner ceiling surface or outer ceiling surface); Building materials for forming walls or ceilings of buildings (eg, ceiling tiles, wood components, gypsum boards, etc.); Interior bulkheads; Metal sheet; Glass substrates; door; window; Components of mechanical devices; An instrument component (ie, instrument inner surface or instrument outer surface); The surface of the pipe or hose; Computer or electronic components; Recording or playback devices; Instrument housings or cases, computers, and the like.

II. Method of making a multilayer article

The invention also relates to the structured film described above and a method of making a composite article comprising the same. In one embodiment of the present invention, a method of making a structured film includes extruding a sheet of melt extrudate from a die; Contacting the molten extrudate with the tool such that a portion of the molten extrudate can enter into a plurality of holes located on the tool outer surface such that (i) the higher air pressure in one or more holes of the tool Creating an air pressure difference between lower air pressures on the surface, and (ii) causing a plurality of protrusions to form along the melt extrudate surface; Moving air in one or more holes of the tool in a direction towards the outer surface of the molten extrudate opposite the tool, thereby (i) reducing the air pressure differential, and (ii) forming protrusion holes in one or more of the plurality of protrusions. step; And cooling the melt extrudate and the plurality of protrusions to form a structured film comprising a substantially flat film portion having a first major surface and a second major surface and a plurality of tubular protrusions extending from at least the first major surface. Include.

In the exemplary structured film manufacturing method, contacting the melt extrudate with a tool may include nipping the melt extrudate between a tool comprising a tool roll and a nip roll. . In addition, moving the air may include rotating the tool roll and the nip roll such that the nip roll is not positioned on the outer surface of the molten extrudate opposite the tool. In any exemplary structured film production method, one or more process parameters are adjusted such that the step of moving the air passes through one of the tubular protrusions with a projection hole extending into or through the substantially flat film portion from the first projection end. It can be created within the above. Process parameters that can be adjusted include, but are not limited to, extrudate composition, extrudate temperature, tool temperature, tool speed, tool hole depth, melt extrudate sheet thickness, or combinations thereof.

In another exemplary structured film production method, one or more process parameters are adjusted such that the step of moving the air creates a projection hole in the one or more tubular projections extending into or through the substantially flat film portion from the first projection end. To form a bubble portion in fluid communication with the protruding hole. In this embodiment, the bubble portion may be located (i) within the substantially flat film portion, (ii) below the second major surface of the substantially flat film portion, or (iii) both (i) and (ii). Process parameters that can be adjusted to form bubbles include, but are not limited to, extrudate composition, extrudate temperature, tool temperature, tool speed, tool hole depth, melt extrudate sheet thickness, or a combination thereof.

In some embodiments in which a bubble portion is formed in one or more tubular protrusions, the method of making a structured film may further include opening the bubble portion to provide an opening that extends completely through one or more of the tubular protrusions. Opening the bubble section may include removing a tip of the bubble section (eg, cutting the tip from the bottom surface of the bubble section), drilling a bubble section (eg, with a needle or other sharp object), protruding hole Pressurizing, heating the tip of the bubble, or any combination of the opening steps described above.

In another exemplary structured film production method, one or more process parameters are adjusted to provide an opening in which the step of moving the air extends through one or more tubular protrusions (eg, without the need for the opening step described above). To create projection holes in the one or more tubular projections that extend from the first projection end through the substantially flat film portion. Furthermore, process parameters that can be adjusted to form openings that extend fully through one or more tubular protrusions may include extrudate composition, extrudate temperature, tool temperature, tool speed, tool hole depth, melt extrudate sheet thickness, or their Combinations include but are not limited to.

In another exemplary structured film production method, one or more of the process parameters described above are adjusted such that the step of moving the air is performed on the second major surface of the structured film from above the first major surface of the structured film. Causing one or more tubular protrusions to extend down. In this embodiment, the method removes at least a portion of the thermoformed material below the second outer surface of the structured film, if necessary, after the cooling step so that it is below the second major surface from the first protrusion end above the first major surface. Providing an opening that extends completely through the one or more tubular protrusions of the structured film to the second protrusion end of the substrate. In this embodiment, the method removes substantially all of the thermoformed material located below the second major surface of the structured film such that the structured film comprises a plurality of tubular protrusions along only the first major surface of the structured film. And may optionally also comprise a step of making it.

In one preferred embodiment, a method of making a structured film comprises extruding a melt extrudate from a die into a nip formed between a rotary tool roll and a rotary nip roll; Pressing a portion of the molten extrudate into a plurality of holes located in the rotary tool roll, thereby (i) between the higher air pressure in one or more holes of the rotary tool roll and the lower air pressure on the outer surface of the molten extrudate opposite the rotary tool roll. Creating an air pressure difference, and (ii) forming a plurality of protrusions along the melt extrudate surface; Rotating the tool roll and the nip roll to move air in one or more holes of the rotating tool roll in a direction toward the outer surface of the molten extrudate opposite the rotating tool roll to form protrusion holes in one or more of the plurality of protrusions; And cooling the melt extrudate and the plurality of projections to a temperature below the softening temperature of the melt extrudate and the plurality of projections. This example method may be performed using a device such as the example device 50 shown in FIG. 5.

As shown in FIG. 5, the exemplary apparatus 50 includes a die assembly 51 through which the melt extrudate 52 exits. The melt extrudate 52 proceeds to point P _A , where the melt extrudate 52 is rotated in the first direction as indicated by arrow A ₁ and the nip roll 53 and arrow A _2. Passes between tool rolls 54 rotating in opposite directions as indicated by. At point P _A , nip roll 53 presses a portion of molten extrudate 52 into a hole (not shown) in outer surface 59 of tool roll 54. The outer surface 58 of the nip roll 53 is typically smooth and optionally coated with a release material (such as, for example, silicone or PTFE). As the melt extrudate 52 fills the holes (not shown) in the outer surface 59 of the tool roll 54 due to the force by the outer surface 58 of the nip roll 53, (not shown) ) The air pressure in the individual holes increases, so that the air pressure difference between the higher air pressure in the individual holes (not shown) and the lower air pressure on the outer surface 56 of the molten extrudate 52 opposite the tool roll 54. To form.

As the nip roll 53 and tool roll 54 rotate, the outer surface 58 of the nip roll 53 is displaced from the outer surface 56 of the melt extrudate 52, which is not shown. Air in the individual holes is allowed to move through the melt extrudate in the individual holes (not shown) towards the outer surface 56 of the melt extrudate 52 (ie, toward lower air pressure). Near the point P _B , the melt extrudates in individual holes (not shown) of the outer surface 59 of the tool roll 54 begin to cure. The molten extrudate adjacent to the outer surface 59 of the tool roll 54 and the individual hole sidewall surfaces is believed to cure prior to the center of the melt extrudate at the central location of the individual holes. As the melt extrudate 52 moves from point P _B to point P _C along the outer surface 59 of the tool roll 54, the above-described air movement causes holes to appear in the melt extrudate This moves rapidly toward the outer surface 56 of the melt extrudate 52. As noted above, the air movement may (i) be a hole extending into or through the substantially flat film portion of the melt extrudate 52, (ii) within and / or in the substantially flat film portion of the melt extrudate 52. Bubbles formed thereunder, (iii) holes extending fully through the substantially flat film portion of the melt extrudate 52, (iv) a second below the second major surface of the substantially flat film portion of the melt extrudate 52 Protrusion end, or (v) any combination of (i)-(iv).

Near the point P _C , the molten extrudate 52 and the tubular protrusion 12 formed therein are substantially cured. As the molten extrudate 52 having tubular protrusion 12 therein moves along the outer surface 59 of the tool roll 54, the outer surface 56 of the substantially cured molten extrudate 52 becomes It comes into contact with the outer surface 60 of the take-off roll 55 which rotates in the direction as indicated by arrow A ₃ . At point P _D , the substantially cured melt extrudate 52 is separated from the outer surface 59 of the tool roll 54 and along the outer surface 60 of the take-off roll 55 an arrow A Proceeding in the direction as indicated by ₄ ), a structured film 57 having a tubular protrusion 12 therein is produced.

The disclosed exemplary structured film manufacturing method of the present invention can be used to form a structured film comprising any of the aforementioned polymeric materials and optional additives. Typically, the thermoforming method step comprises melt extruding the film forming thermoformable material at a melt extrusion temperature in the range of about 120 ° C. to about 370 ° C.

A major advantage of the disclosed structured film production methods of the present invention over conventional perforated film production methods is the ability to produce structured films with relatively large pore depths and tubular protrusion lengths while maintaining thin and substantially flat film portions. Being able to separate the hole depth and the tubular protrusion length from the thickness of the substantially flat film portion provides the ability to generate new production of structured film for various applications. For example, the increased hole depth provides advantages such as an increase in air mass and friction drag through the tubular protrusion when sound waves are transmitted through the hole. Separating the hole length and the tubular protrusion length from the thickness of the substantially flat film portion also allows added degrees of freedom in developing a product with increased acoustic mass resistance independent of the bending stiffness of the film.

The disclosed structured film production method of the present invention also provides an opportunity for producing structured films with relatively large hole depth / hole diameter ratios that could not be achieved in the low cost manufacturing operations prior to the present invention. By way of example, in one exemplary embodiment, the disclosed method can produce a structured film in which at least a portion of the tubular protrusion has a protrusion hole length to protrusion hole diameter ratio of at least about 1: 1. In another exemplary embodiment, the disclosed method can produce a structured film having a projection hole length to projection hole diameter ratio wherein at least a portion of the tubular projection is at least about 3: 1 and at least 5: 1 or more.

In addition, the ability to provide a relatively thin substantially flat film portion allows for a lower basis weight film, which may be advantageous in weight conscious applications. Lower basis weights of the structured films of the present invention also lead to lower raw material usage and lower manufacturing costs. The disclosed method has a projection hole length to average film portion thickness ratio of at least a portion of the tubular protrusion of at least about 1.1: 1, and in some embodiments a protrusion hole length to average film portion thickness ratio of at least about 5: 1, and in some embodiments at least Structured films can be prepared having a protruding hole length to average film portion thickness ratio of at least about 10: 1.

The disclosed structured film manufacturing method of the present invention may utilize a tool to produce a tubular protrusion having a protrusion length (L) as described above. For example, a suitable tool includes a plurality of holes in the outer surface of the tool, where the holes have an average tool hole depth of up to about 1.5 cm (588 mils). In another embodiment, a suitable tool has an average tool hole depth of between about 27.9 μm (1.1 mils) and about 3.0 mm (117 mils), and in other embodiments from about 747 μm (29.4 mils) to about 1.5 mm (58.8 mils) It may include a hole having an average tool hole depth.

Suitable tools may also have holes therein, wherein the holes have one or more hole cross-sectional shapes to form tubular protrusions having a desired cross-sectional shape. Suitable hole cross-sectional shapes include, but are not limited to, circles, ellipses, polygons, squares, triangles, hexagons, multileafs, or any combination thereof.

In addition, suitable tools may have any desired hole density along the outer surface of the tool (eg, at the outer surface 59 of the tool roll 54). For example, the tool may have a hole density of up to about 1000 holes per cm 2 of the outer surface area of the tool. Typically, the tool has a hole density that ranges from about 10 holes per cm 2 to about 300 holes per cm 2 of the tool's outer surface area.

The disclosed structured film manufacturing method may further comprise attaching one or more additional layers to the structured film. In one exemplary embodiment, a method of making a structured film includes a first projection end of the tubular projection, a second projection end of the tubular projection, a second major surface of the substantially flat film portion, or these prior to the cooling step described above. Contacting the combination of at least one additional layer. In another exemplary embodiment, a method of making a structured film includes attaching additional layers to the structured film after formation of the structured film (eg, using a thermal lamination process step). As mentioned above, the additional layers may be color containing layers, nonwoven fabrics, woven fabrics, knitted fabrics, foam layers, films, paper layers, layers of particles, foil layers, decorative cloth layers, membranes, reticular bodies, meshes, wiring or tubing network; Or any combination thereof, but is not limited to such.

In addition to the structured film forming step described above, the disclosed structured film manufacturing method may include one or more of the following process steps:

(1) advancing the structured film along the process path towards further processing operations;

(2) contacting one or more additional layers with the outer surface of the structured film;

(3) removing a portion of the one or more tubular protrusions extending below the second major surface of the structured film to form an opening extending the full length of the tubular protrusion;

(4) removing any portion of the one or more tubular protrusions extending below the second major surface of the structured film such that the tubular protrusions do not extend below the second major surface of the structured film;

(5) removing a portion of the one or more tubular protrusions extending above the first major surface of the structured film;

(6) coating the structured film with a surface treatment or other composition (eg, flame retardant composition, adhesive composition, or printing layer);

(7) attaching the structured film to a cardboard or plastic tube;

(8) winding the structured film in the form of a roll:

(9) slitting the structured film to form two or more divided rolls;

(10) when present, applying a release liner over the exposed pressure sensitive adhesive layer; And

(11) attaching the structured film to other substrates through any other attachments, including but not limited to, adhesives or clips, brackets, bolts / screws, nails, and straps.

III. How to use structured film

The structured film (and composite article comprising the structured film) of the present invention can be used in a variety of applications. Structured films are particularly useful for acoustic applications such as sound absorption and sound barrier applications. In one exemplary embodiment, the method of using the structured film includes a sound absorption method in a predetermined area, the method comprising surrounding at least a portion of the area with the structured film. In some embodiments, the entire area may be surrounded by the structured film alone or in combination with one or more optional layers as described above.

Surrounding the region can include positioning the structured film over at least a portion of the region, wherein the structured film is one of the structured films described above alone or in combination with one or more additional layers. It may include any. In some embodiments, enclosing may include positioning a structured film or a composite article comprising a structured film over at least a portion of the region. The step of enclosing may further comprise attaching the structured film (or composite article comprising the structured film) to the substrate. Any of the aforementioned attachments can be used to attach a structured film (or a composite article comprising a structured film) to a given substrate. Suitable substrates include walls of buildings, ceilings of buildings, building materials forming walls or ceilings of buildings, metal sheets, glass substrates, doors, windows, vehicle components, components of mechanical devices, electronic devices (e.g., printers, Hard drives, etc.), or components of the instrument.

In another embodiment of the present invention, a method of using a structured film includes a method of providing a sound barrier between a sound-generating body and a predetermined area. In this exemplary method, the method can include providing a structured film (or a composite article comprising the structured film) between the sound-generating body and the region. The sound-generating body can be any object that generates a sound, including but not limited to a vehicle power source, part of a mechanical device, a motor or other moving component of an instrument, an electronic device such as a television, an animal, and the like.

The region in any one of the exemplary methods of using the structured film (or composite article comprising the structured film) can be any region where sound is absorbed and / or limited from. Suitable areas include the interior of the room; The interior of the vehicle; Part of a mechanism; Instrument; Separate winding areas of office or industrial zones; Recording or playback area; The interior of a theater or concert hall; An anechoic, analytical or experimental site or chamber in which sound may be harmful; And earplugs or earmuffs to disconnect and / or protect ears from noise.

The structured film of the present invention can also be used as a resistive layer in a carpet. In this embodiment, one or more fabric layers are attached to each side of the structured film to form a laminate.

The invention is described above and further described below by way of examples, which should not be construed as limiting the scope of the invention in any way. On the contrary, various other embodiments, modifications, and equivalents thereof may be used, and one of ordinary skill in the art, after reading the description herein, may recall this without departing from the spirit of the invention and / or the scope of the appended claims. It should be clearly understood.

Example 1:

A structure similar to those of the exemplary tubular protrusions 12 shown in FIGS. 2A-2F is prepared using a procedure similar to the example apparatus 50 shown in FIG. 5 and the following procedure. It was. 6.35 cm (2.5 in) Davis-Standard single screw extruder (Davis-Standard, feeding into a 25.4 cm (10 in) PVC cast film extrusion die with a 508 μm (20 mil) die gap The polymer melt was extruded using LLC (available from Pocatuck, Connecticut). The drop die construct was fed into two horizontal roll nips. The tool roll had a diameter of 31.75 cm (12.5 in) and the backup steel roll had a diameter of 30.48 cm (12 in). The tool consisted of a roll with an outer aluminum shell with cylindrical blind holes drilled into the outer surface. The holes had a diameter of 398.8 μm (15.7 mils) and a center spacing of 1.70 mm (67 mils) in the square array. The hole pattern was 20.3 cm (8.0 in) wide around the circumference of the tool roll. The depth of the hole varied around the tool roll. The circumference of the tool roll was divided into three sections. The first section has holes drilled to a depth of 30 mils of 762 μm, while the second section has holes drilled to a depth of 25 mils of 635 μm (20 mils). Had a hole drilled to the depth of.

Two commercially available propylene / ethylene impact copolymers, Huntsman PP AP5165-HA (MFI 65) (available from Huntsman Polymers, Woodlands, TX), and Huntsman PP 14S50V ( MFI 50) was used to form the structured film. The following process conditions were used:

Digital microscopic measurements of the various structural features of the resulting structured film sample were taken. 2C to 2D for reference, the following measurements were taken as shown in Table 2 below. The sample, referred to as the "-1" sample, was treated using a hole depth of 762 μm (30 mils). Samples, referred to as "-2" samples, were treated using a hole depth of 635 μm (25 mils). The sample, referred to as the "-3" sample, was processed using a hole depth of 508 μm (20 mils).

The resulting structured film had hollow tubular protrusions with through holes extending through the substantially flat film portion of the structured film. Pattern # 1 with a hole depth of 762 μm (30 mils) provided the most consistent tubular protrusion features and through holes extending through the substantially flat film portion of the structured film. Other patterns sometimes created through holes, more often creating bubbles or blisters on the second major surface of the structured film.

Sound absorption tests were performed on the samples. An impedance tube tester (Bruel & Kjaer Model 6205 (Norcross, GA) using 64 mm tubes) was used to determine sound absorption coefficients at various frequencies. The test was run using ASTM 1050 with a 25 mm space behind each structured film. The impedance tube test results for exemplary structured films (samples 1-1 and 4-1) of the present invention are shown in FIG.

Example 2:

Procedures and apparatus similar to those used in Example 1 above were used to produce structured films having tubular protrusion configurations similar to those of the exemplary tubular protrusion 12 shown in FIGS. 2A-2F. A structured film was formed using a commercially available polypropylene thermoplastic, ie Huntsman PP AP5165-HA with an MFI of 65. The following process conditions were used:

Digital microscopic measurements of the various structural features of the resulting structured film sample were taken as described in Example 1. The results are shown in Table 4 below. As in Example 1, a sample referred to as a "-1" sample was treated using a hole depth of 762 μm (30 mils) and a sample referred to as a “-2” sample was a hole of 635 μm (25 mils) The depth was processed and the sample, referred to as the "-3" sample, was processed using a hole depth of 508 μm (20 mils).

The resulting structured film had hollow tubular protrusions with through holes extending through the substantially flat film portion of the structured film. Each of patterns # 1, # 2, and # 3 provided through holes and consistent tubular protrusion features extending through the substantially flat film portion of the structured film.

Sound absorption tests were performed on samples as described in Example 1. The impedance tube test results for exemplary structured films (samples 7-3, 8-1 and 9-3) of the present invention are shown in FIG.

Example 3

A structure similar to those of the exemplary tubular protrusions 12 shown in FIGS. 2A-2F is prepared using a procedure similar to the example apparatus 50 shown in FIG. 5 and the following procedure. It was. From a 6.35 cm (2.5 in) Davis-Standard Single Extruder (Davis-Standard, ELC, Pocatuck, CT) to feed into a 30.5 cm (12 in) cast film extrusion die with a 508 μm (20 mil) die gap Available) to extrude the polymer melt. The drop die construct was fed into two horizontal roll nips. The tool roll had a diameter of 31.75 cm (12.5 in) and the backup steel roll had a diameter of 30.48 cm (12 in). The tool consisted of a roll with an outer aluminum shell with cylindrical blind holes drilled into the outer surface. The holes had a diameter of 0.5 mm (19.7 mils) and a center spacing of 1.70 mm (67 mils) in the square array. The hole pattern was 20.3 cm (8.0 in) wide around the circumference of the tool roll. The depth of the hole varied around the tool roll. The circumference of the tool roll was divided into four sections. The first section had holes drilled to a depth of 1.143 mm (45 mils), while the second section had holes drilled to a depth of 965 μm (38 mils), and the third section had 787 μm (31 mils) The fourth section had holes drilled to a depth of 330 μm (13 mils).

A structured film was formed using a commercially available propylene / ethylene impact copolymer, namely Huntsman PP AP5165-HA (MFI 65) (commercially available from Huntsman Polymers, Woodlands, TX). The following process conditions were used:

The process conditions in Table 5 were the optimum run conditions for hole pattern 2 at a hole depth of 965 μm (38 mils). Digital microscopic measurements of the various structural features of the resulting structured film sample were taken. 2C to 2D for reference, the following measurements were taken as shown in Table 6 below.

The resulting structured film had hollow tubular protrusions with through holes extending through the substantially flat film portion of the structured film.

Sound absorption tests were performed on the samples. An impedance tube tester (Bruel & Kea Model 6205 (Norcross, GA) using 64 mm tubes) was used to determine sound absorption coefficients at various frequencies. The test was run using ASTM 1050 with a 25 mm space behind each structured film. The impedance tube test results for an exemplary structured film of the present invention (sample E060504-16) are shown in FIG. 7.

Although this specification has been described in detail with respect to specific embodiments, those skilled in the art should understand that modifications, variations, and equivalents of these embodiments can be readily devised when the above description is understood. Accordingly, the scope of the invention should be assessed as that of the appended claims and any equivalents thereof.

Claims (41)

A substantially flat film portion having a first major surface, a second major surface, and an average film portion thickness; And A plurality of tubular protrusions extending from the substantially flat film portion Including, One or more tubular protrusions, (Iii) a hole extending into or through the substantially flat film portion from the first protrusion end on the first major surface, the hole having a protrusion hole diameter in the range of 25.4 μm (1 mil) to 254 μm (10 mil) Has-, (Ii) a projection sidewall surrounding at least a portion of the aperture and having an outer projection sidewall surface, an inner projection sidewall surface and a projection sidewall thickness, and (Iii) a projection length extending a predetermined distance from the first projection end to the first major surface, wherein the ratio of the projection length to the average film portion thickness is at least 3.5; Including, The projected wall thickness of at least a portion of the at least one tubular protrusion is at least an average film portion thickness. The structured film of claim 1, wherein the one or more tubular protrusions have a second protrusion end located below the second major surface. A substantially flat film portion comprising a thermoformable material having a first major surface, a second major surface and an average film portion thickness; And A plurality of tubular protrusions extending from the substantially flat film portion Including, One or more tubular protrusions, (Iii) a hole extending into or through the substantially flat film portion from the first protrusion end on the first major surface, the hole having a protrusion hole diameter in the range of 25.4 μm (1 mil) to 254 μm (10 mil) Has-, (Ii) a projection sidewall surrounding at least a portion of the aperture and comprising the thermoformable material and having an outer projection sidewall surface, an inner projection sidewall surface and a projection sidewall thickness, and (Iii) the end-to-end protrusion length extending from the first protrusion end to the second protrusion end below the second major surface by a predetermined distance; Including, The at least one tubular protrusion having an upper protrusion length extending a predetermined distance from the first protrusion end to the first major surface, wherein the ratio of the upper protrusion length to the average film portion thickness is at least 3.5, and after film formation Structured film without protrusion forming orientation. 4. The aperture of claim 1 or 3, wherein the aperture extends from the first protrusion end on the first major surface to the second protrusion end through the substantially flat film portion, thereby opening an opening through the structured film. Providing structured film. 4. The method of claim 3, wherein the at least one tubular protrusion has a bubble portion in fluid communication with the aperture, wherein the bubble portion is (i) within the substantially flat film portion, (ii) below the second major surface, or (iii). ) The structured film in both (iii) and (ii). 6. The method of claim 1, wherein the first additional layer, the second major surface, or the tubular protrusion is positioned on and attached to the first protrusion end of the tubular protrusion. 7. A second additional layer located on and attached to the second protrusion end, or in combination with both the first additional layer and the second additional layer. A method of sound absorption in a given area, comprising the step of enclosing at least a portion of the given area with the structured film of claim 1. delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete delete

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